A light emitting diode (LED) has a low working voltage, low power loss, high light emitting efficiency, short response time, pure light color, sturdy structure, high impact resistance, high vibration endurance, stable performance, light weight, small volume and low cost. The promotion of the technology has helped to increase the brightness of the LED, and the LEDs are being used in increasingly diverse applications such as large-scale display screen, status indication, symbol lighting, signal display, backlight of a liquid crystal display (LCD) and lighting in car.
The conventional LED base is formed by an injection molding process to combine a lead frame, thereby forming a package structure. The lead frame is electrically connected to the electrode of the LED chip. The base is formed by an injection molding process to package the LED chip and hold the lead frame, wherein a recessed zone is formed in the base to dispose the LED chip.
However, in the package structure of the conventional LED, the recessed zone is defined by the base formed by injection molding, and an opening is formed in the base, so that the extractive light emitted from the LED chip can form a regular circular shape. The material of the base is heat-resistant and not pervious to light, such as polyphthalamide (PPA). When the LED is on, part of the light is not directly emitted out through the opening, but emitted inside the base, e.g. toward the side wall of the base, then absorbed, reflected or scattered on the side wall. Only a little light emitted toward the side wall can pass through the opening, and most light is absorbed by the material of the base, so that the light emitting efficiency is reduced by the base.